System and method for determining a position on an external surface of an object

Abstract

The present system and method determine a position on an external surface of an object. The system comprises a magnetic field measurement module and an ultrasound measurement module. A control unit stores a magnetic field map of the object comprising a first plurality of reference areas of the external surface of the object and associated reference magnetic field value. The control unit also stores an ultrasound map of the object comprising a second plurality of reference areas of the external surface of the object and associated reference ultrasound characteristic. The processing unit determines: a subset of the reference areas for which the associated reference magnetic field value is substantially equal to a measured magnetic field value, a subset of the reference areas for which the associated reference ultrasound characteristic is substantially equal to a measured ultrasound characteristic, and determines the position on the external surface of the object.

What is claimed is: 
     
       1. A system for determining a position on an external surface of an object, the system comprising:
 an apparatus comprising:
 a magnetic field measurement module for measuring a magnetic field value induced by the object; 
 an ultrasound measurement module for generating an ultrasound signal, receiving a corresponding reflected ultrasound signal reflected by the object, and measuring an ultrasound characteristic of the reflected ultrasound signal; and 
 a control unit comprising: 
 memory for storing:
 a magnetic field map of the object, the magnetic field map comprising a first plurality of reference areas of the external surface of the object, each one of the first plurality of reference areas having an associated reference magnetic field value, and an ultrasound map of the object, the ultrasound map comprising a second plurality of reference areas of the external surface of the object, each one of the second plurality of reference areas having an associated reference ultrasound characteristic; 
 
 a processing unit for:
 determining a subset of the first plurality of reference areas for which the associated reference magnetic field value is substantially equal to the measured magnetic field value; 
 determining a subset of the second plurality of reference areas for which the associated reference ultrasound characteristic is substantially equal to the measured ultrasound characteristic; and 
 correlating the subset of the first plurality of reference areas and the subset of the second plurality of reference areas to determine the position on the external surface of the object. 
 
 
 
     
     
       2. The system of  claim 1 , wherein the measured ultrasound characteristic comprises at least one of the following: delay of receipt of the reflected ultrasound signal, a gradient of the reflected ultrasound signal, and a pattern of the reflected ultrasound signal. 
     
     
       3. The system of  claim 1 , wherein the object is a patient simulator for simulating medical procedures. 
     
     
       4. The system of  claim 1 , wherein the apparatus is a simulator of a medical instrument. 
     
     
       5. The system of  claim 1 , wherein the control unit further comprises a display for displaying a representation of the object and a representation of the determined position on the representation of the object. 
     
     
       6. The system of  claim 1 , further comprising the object, the object consisting of a vest or a patient simulator covered by a vest, the vest comprising a plurality of areas corresponding to the second plurality of reference areas of the external surface of the object, the plurality of areas being adapted for reflecting the ultrasound signal generated by the ultrasound measurement module of the apparatus. 
     
     
       7. A method for determining a position on an external surface of an object, the method comprising:
 storing by a memory of a control unit a magnetic field map of the object, the magnetic field map comprising a first plurality of reference areas of the external surface of the object, each one of the first plurality of reference areas having an associated reference magnetic field value; 
 storing by the memory of the control unit an ultrasound map of the object, the ultrasound map comprising a second plurality of reference areas of the external surface of the object, each one of the second plurality of reference areas having an associated reference ultrasound characteristic; 
 measuring by a magnetic field measurement module of an apparatus a magnetic field value induced by the object; 
 generating by an ultrasound measurement module of the apparatus an ultrasound signal; 
 receiving by the ultrasound measurement module of the apparatus a corresponding reflected ultrasound signal reflected by the object; 
 measuring by the ultrasound measurement module of the apparatus an ultrasound characteristic of the reflected ultrasound signal; 
 transmitting by a communication interface of the apparatus the measured magnetic field value and the measured ultrasound characteristic to the control unit; 
 receiving by a communication interface of the control unit the measured magnetic field value and the measured ultrasound characteristic; 
 determining by a processing unit of the control unit a subset of the first plurality of reference areas for which the associated reference magnetic field value is substantially equal to the measured magnetic field value; 
 determining by the processing unit of the control unit a subset of the second plurality of reference areas for which the associated reference ultrasound characteristic is substantially equal to the measured ultrasound characteristic; and 
 correlating by the processing unit of the control unit the subset of the first plurality of reference areas and the subset of the second plurality of reference areas to determine the position on the external surface of the object. 
 
     
     
       8. The method of  claim 7 , wherein the measured ultrasound characteristic comprises at least one of the following: delay of receipt of the reflected ultrasound signal, a gradient of the reflected ultrasound signal, and a pattern of the reflected ultrasound signal. 
     
     
       9. The method of  claim 8 , wherein the object is a patient simulator for simulating medical procedures. 
     
     
       10. The method of  claim 8 , wherein the apparatus is a simulator of a medical instrument. 
     
     
       11. The method of  claim 8 , wherein the control unit further comprises a display for displaying a representation of the object and a representation of the determined position on the representation of the object. 
     
     
       12. The method of  claim 8 , wherein the object consists of a vest or a patient simulator covered by a vest, the vest comprising a plurality of areas corresponding to the second plurality of reference areas of the external surface of the object, the plurality of areas being adapted for reflecting the ultrasound signal generated by the ultrasound measurement module of the apparatus.